To meet the demand for wireless data traffic, which has increased since the deployment of 4th-generation (4G) communication systems, efforts have been made to develop an improved 5th-generation (5G) or pre-5G communication system. The 5G or pre-5G communication system is also called a ‘beyond 4G network’ or a ‘post long-term evolution (LTE) system’.
It is considered that the 5G communication system will be implemented in millimeter wave (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To reduce propagation loss of radio waves and increase a transmission distance, a beam forming technique, a massive multiple-input multiple-output (MIMO) technique, a full dimensional MIMO (FD-MIMO) technique, an array antenna technique, an analog beam forming technique, and a large scale antenna technique are discussed (or proposed) in 5G communication systems.
In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, a device-to-device (D2D) communication, a wireless backhaul, a moving network, a cooperative communication, coordinated multi-points (CoMP), reception-end interference cancellation, and the like.
In the 5G system, a hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM) (frequency and quadrature amplitude modulation (FQAM)) and a sliding window superposition coding (SWSC) as an advanced coding modulation (ACM) scheme, and a filter bank multi carrier (FBMC) scheme, a non-orthogonal multiple access (NOMA) scheme, and a sparse code multiple access (SCMA) scheme as an advanced access technology have been developed.
The internet, which is a human centered connectivity network where humans generate and consume information, is now evolving to the internet of things (IoT) where distributed entities, such as things, exchange and process information without human intervention. The internet of everything (IoE), which is a combination of the IoT technology and the big data processing technology through connection with a cloud server, has emerged.
As technology elements, such as “sensing technology”, “wired/wireless communication and network infrastructure”, “service interface technology”, and “security technology” have been demanded for IoT implementation, a sensor network, a machine-to-machine (M2M) communication, machine type communication (MTC), and so forth have been recently researched.
Such an IoT environment may provide intelligent internet technology services that create a new value to human life by collecting and analyzing data generated among connected things. IoT may be applied to a variety of fields including smart home, smart building, smart city, smart car or connected cars, smart grid, health care, smart appliances and advanced medical services through convergence and combination between existing information technology (IT) and various industrial applications.
Accordingly, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as a sensor network, MTC, and M2M communication may be implemented by beamforming, MIMO, and array antennas. Application of a cloud radio access network (RAN) as the above-described big data processing technology may also be considered to be as an example of convergence between the 5G technology and the IoT technology.
Meanwhile, a significant increase in data rate in a wireless network has required a high frequency efficiency in a wireless communication system. For example, a wireless communication system with an enhanced frequency efficiency compared to a wireless communication system which is based on an orthogonal frequency division multiplexing (OFDM) scheme (e.g., an LTE system) has been required.
The OFDM scheme uses a guard band and a periodic cyclic prefix (CP). The use of the guard band and the CP may decrease a frequency efficiency in a system.
Generally, a frequency efficiency in a wireless communication system may be affected by self-interference amount and a spectrum confinement characteristic. For example, an FBMC scheme uses a filter which uses a good spectrum confinement characteristic, and the FBMC scheme improves a spectrum confinement characteristic which affects a frequency efficiency thereby a CP is unused or decreased.
Meanwhile, if a wireless communication system is able to decrease self-interference amount, the wireless communication system may support a high order-modulation and coding scheme (MCS) thereby improving a frequency efficiency.
As described above, if a wireless communication system is able to support a high order-modulation scheme by decreasing self-interference amount and decrease a guard band by improving a spectrum confinement characteristic, a frequency efficiency may be increased.
However, in a wireless communication system, it is very difficult to improve a spectrum confinement characteristic while decreasing self-interference amount. This is why there is a trade-off relation between the self-interference amount and the spectrum confinement characteristic, and this is proved by a “Balian-Low theorem”. For example, if self-interference amount is 0 (zero), it is impossible that a spectrum confinement characteristic is completely confined within a predetermined band.
In the OFDM scheme, a self-interference amount is 0 (zero), but a spectrum confinement characteristic is relatively poor, as about 10% of an entire band needs to be allocated for a guard band. Further, an FBMC scheme which uses a filter with a good performance does not satisfy all of two characteristics, e.g., self-interference amount and a spectrum confinement characteristic.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.